1. Field of the Invention
The present invention relates to a substrate processing system and a substrate processing method.
2. Description of the Related Art
In a photolithography process in the process of fabricating a semiconductor device, resist coating processing in which a resist film is formed on the front face of a semiconductor wafer (hereinafter referred to as xe2x80x9ca waferxe2x80x9d) and exposure processing are performed. A spin coating method in which the wafer is coated with a resist solution while being rotated is frequently used for this resist coating processing, and a rotary coating apparatus is used as a processing apparatus.
When resist coating processing is performed, it is necessary to maintain the temperature and humidity of an atmosphere in a coating apparatus constant for improving uniformity, reproducibility, and controllability of the thickness of a coating film.
The atmospheric pressure in a clean room where the coating apparatus is installed, however, slightly changes according to the season, arrival of low atmospheric pressure or high atmospheric pressure, or the condition of air-conditioning equipment. The thickness of a coating film formed on the front face of the wafer changes according to a change in the atmospheric pressure in the clean room even if the temperature and humidity of the atmosphere is maintained constant.
To solve such a problem, Japanese Patent Laid-open No. Hei 5-144721 discloses a photo-resist coating apparatus in which the atmospheric pressure in a coating cup in the coating apparatus is detected by an atmospheric pressure detecting section, the rotation speed of a motor is decided based on a detection signal by a data computing section, by an output therefrom, the wafer is rotated by the motor under the control of a motor rotation controlling section and coated with a coating solution, and which the thickness of the coating film is maintained constant by changing the rotation speed of the motor for rotating the wafer according to a change in the atmospheric pressure in a coating processing section.
The coating apparatus disclosed in Japanese Patent Laid-open No. Hei 5-144721, however, is a means for individually coping with a change in atmospheric pressure in each coating apparatus. In an actual clean room where photo-resist processing for a substrate is performed, a plurality of coating apparatus of various kinds are provided. Therefore, the application of the aforesaid apparatus to all the coating apparatus of different kinds causes complication and needs considerable plant and equipment investment, resulting in an increase in cost.
Also in exposure processing, the size of photo-resist pattern formed after exposure and developing has changed due to a change in the atmospheric pressure in the aligner even when the thickness of a resist film is the same.
An object of The present invention is to provide a substrate processing system or a substrate processing method capable of holding plant and equipment investment to minimum without causing complication of apparatus, and maintaining the thickness of a coating film at a predetermined thickness even when the atmospheric pressure changes in a clean room having a plurality of coating apparatus.
Another object of the present invention is to provide a substrate processing system or a substrate processing method capable of maintaining the size of a photo-resist pattern at a predetermined size even when the atmospheric pressure changes in the system including a coating apparatus and an aligner.
To attain these objects, in a first aspect of the present invention, a substrate processing system, comprising: a plurality of rotary coating apparatus, disposed in a room, each for coating a substrate with a chemical supplied from above the substrate while rotating the substrate; atmospheric pressure measuring means for measuring the atmospheric pressure in the room; and controlling means for controlling rotation speed at the time of coating in the rotary coating apparatus based on an atmospheric pressure value measured by the atmospheric pressure measuring means, is provided.
According to the aforesaid structure, the atmospheric pressure measuring means is provided in the room having the plurality of rotary coating apparatus, and the measured value of the atmospheric pressure in the room is used as a judgment standard for the control of rotation speed in each of the rotary coating apparatus, whereby it is unnecessary to provide a barometer in each of the rotary coating apparatus. Moreover, the rotation speed at the time of coating is controlled based on the measured value, and consequently the thickness of a coating film can be controlled, and thus the substrate can be coated with a chemical at a predetermined film thickness even when the atmospheric pressure changes.
In a second aspect of the present invention, a substrate processing system, comprising: a first rotary coating apparatus, disposed in a room, for coating a substrate with a first chemical supplied from above the substrate while rotating the substrate; a second rotary coating apparatus, disposed in the room, for coating the substrate with a second chemical supplied from above the substrate while rotating the substrate; atmospheric pressure measuring means for measuring the atmospheric pressure in the room; controlling means for controlling rotation speed at the time of coating in the first rotary coating apparatus based on an atmospheric pressure value measured by the atmospheric pressure measuring means; temperature and humidity measuring means for measuring the temperature and humidity in the second rotary coating apparatus; and controlling means for controlling rotation speed at the time of coating in the second rotary coating apparatus based on a temperature value and a humidity value measured by the temperature and humidity measuring means, is provided.
According to the aforesaid structure, it can be selected according to the type of resist whether the rotation speed is controlled or the temperature and humidity are controlled, whereby the thickness of a coating film can be controlled efficiently even if the types of resists are different.
In a third aspect of the present invention, a substrate processing method, comprising the steps of: measuring the atmospheric pressure in a room where a rotary coating apparatus for coating a substrate with a chemical supplied from above the substrate while rotating the substrate is disposed; and controlling rotation speed at the time of coating in the rotary coating apparatus based on an atmospheric pressure value measured in the measuring step, is provided.
According to the aforesaid structure, the thickness of a coating film can be controlled, and thus the substrate can be coated with the chemical at a predetermined film thickness even when the atmospheric pressure changes.
In a fourth aspect of the present invention, a substrate processing system, comprising: a rotary coating apparatus, disposed in a room, for coating a substrate with a chemical supplied from above the substrate while rotating the substrate; atmospheric pressure measuring means for measuring the atmospheric pressure in the room; mixing means for mixing a resist solution and a solvent to produce the chemical; and controlling means for controlling the mixing ratio of the resist solution to the solvent in the mixing means based on an atmospheric pressure value measured by the atmospheric pressure measuring means, is provided.
According to the aforesaid structure, the atmospheric pressure measuring means is provided in the room having a plurality of the rotary coating apparatus, and the measured value of the atmospheric pressure in the room is used as a judgment standard for the control of rotation speed in each of the rotary coating apparatus, whereby it is unnecessary to provide a barometer in each of the rotary coating apparatus. Moreover, the rotation speed at the time of coating is controlled based on the measured value, and consequently the thickness of a coating film can be controlled, and thus the substrate can be coated with the chemical at a predetermined film thickness even when the atmospheric pressure changes.
In a fifth aspect of the present invention, a substrate processing method, comprising the steps of: measuring the atmospheric pressure in a room where a rotary coating apparatus for coating a substrate with a chemical supplied from above the substrate while rotating the substrate is disposed; and controlling the mixing ratio of a resist solution to a solvent based on an atmospheric pressure value measured in said measuring step, is provided.
According to the aforesaid structure, the thickness of a coating film can be controlled, and thus the substrate can be coated with the chemical at a predetermined film thickness even when the atmospheric pressure changes.
In a sixth aspect of the present invention, a substrate processing system, comprising: a rotary coating apparatus for coating a substrate with a chemical supplied from above the substrate while rotating the substrate to form a coating film; an aligner for exposing the coating film; atmospheric pressure measuring means for measuring the atmospheric pressure in the aligner; and controlling means for controlling rotation speed at the time of coating in the rotary coating apparatus based on an atmospheric pressure value measured by the atmospheric pressure measuring means, is provided.
According to the aforesaid structure, the thickness of the coating film can be controlled in consideration of a change in the size of a photo-resist pattern due to a change in atmospheric pressure at the time of exposure. As a result, a photo-resist pattern with a stable size can be always obtained without being influenced by a change in atmospheric pressure. Furthermore, the rotary coating apparatus and the aligner may be disposed in the same room, and the atmospheric pressure measuring means may be provided in the room.
In a seventh aspect of the present invention, a substrate processing method, comprising the steps of: measuring the atmospheric pressure in an aligner for performing exposure processing for a substrate on which a coating film is formed; rotating the substrate while controlling rotation speed based on an atmospheric pressure value measured in said measuring step and coating the substrate with a chemical supplied from above the substrate to form the coating film; and subjecting the coating film to exposure processing in the aligner, is provided.
According to the aforesaid structure, the thickness of the coating film can be controlled in view of a change in the size of a photo-resist pattern due to a change in atmospheric pressure at the time of exposure. As a result, a photo-resist pattern with a stable size can be always obtained without being influenced by a change in atmospheric pressure.
In an eighth aspect of the present invention, a substrate processing system, comprising: a rotary coating apparatus for coating a substrate with a chemical supplied from above the substrate while rotating the substrate to form a coating film; an aligner for exposing the coating film; atmospheric pressure measuring means for measuring the atmospheric pressure in the aligner; mixing means for mixing a resist solution and a solvent to produce the chemical; and controlling means for controlling the mixing ratio of the resist solution to the solvent in the mixing means based on an atmospheric pressure value measured by the atmospheric pressure measuring means, is provided.
According to the aforesaid structure, the thickness of the coating film can be controlled in consideration of a change in the size of a photo-resist pattern due to a change in atmospheric pressure at the time of exposure. As a result, a photo-resist pattern with a stable size can be always obtained without being influenced by a change in atmospheric pressure. Furthermore, the rotary coating apparatus and the aligner may be disposed in the same room, and the atmospheric pressure measuring means may be provided in the room.
In a ninth aspect of the present invention, a substrate processing method, comprising the steps of: measuring the atmospheric pressure in an aligner for performing exposure processing for a substrate on which a coating film is formed; controlling the mixing ratio of a resist solution to a solvent based on an atmospheric pressure measured in said measuring step to produce a chemical; supplying the chemical onto the substrate and forming the coating film while rotating the substrate; and subjecting the coating film to exposure processing in the aligner, is provided.
According to the aforesaid structure, the thickness of the coating film can be controlled in view of a change in the size of a photo-resist pattern due to a change in atmospheric pressure at the time of exposure. As a result, a photo-resist pattern with a stable size can be always obtained without being influenced by a change in atmospheric pressure.
These objects and still other objects and advantages of the present invention will become apparent upon reading the following specification when taken in conjunction with the accompanying drawings.